And how much do you know about octopuses? Besides, they have eight legs? For example, do you know how many hearts an octopus has? Yes, the question is asked absolutely right. After all, the octopus is not one heart, but several! Or what are these creatures capable of?
Let's figure it out. And not only in how many hearts an octopus has, but in general what kind of animal it is, where it can be found.
Octopus (photo below) refers to cephalopods. These creatures live on the vast expanses of the world, from the Arctic to the Antarctic. Still, octopuses do not tolerate fresh water, they give the salinity of not less than 30 percent.
Their sizes are also very different: from a few centimeters to 6-7 meters. But still the “average height” for them is 1.5-2 meters. The largest octopuses live off the coast of Colombia: some weigh 15–20 kg each, and the length of their tentacles varies from 2 to 2.5 meters, and sometimes even more!
The largest octopus was found in Western Canada. This giant octopus weighed 242 kilograms, and the length of its tentacles reached 10 meters! Awful, probably, a show. Now all the sailors' stories about Krakens, capable of flooding the ship, no longer seem just silly tales.
External structure of the octopus
Octopus has a soft oval body, dressed in a mantle (skin-muscular bag). The mantle can be smooth, with pimples or wrinkled (depending on the type of octopus). Inside, under it, there are organs.
The mantle also serves as a water storage. Since the octopus is a sea creature, it cannot exist without water. In order to get out on dry land, he needs liquid reserves. This reserve is enough for four hours. However, there were cases when octopuses remained on land for more than a day.
On the head of an octopus are large eyes, like most representatives of deep-sea creatures, with square-shaped pupils.
The mouth of the octopus is small, with a pair of strong jaws. Outwardly, it is a bit like a parrot's beak. That is why it is called “beak”. In the mouth is located lingual growth ("odontofor"). On both sides of the body are the gills, which are responsible for the extraction of oxygen from the water.
Eight tentacle arms go from the head, surrounding the mouth. On the inside of each tentacle are suckers, with which the octopus is able to hold prey or stick to underwater objects. On one "hand" of suckers can be up to 220! An interesting fact is that there are visual analyzers in the suction cups. So octopuses are truly unique: able to see with their limbs!
Octopus tentacles most often become the target of an enemy attack. Therefore, nature has endowed the octopuses with the ability to reject their limbs in order to escape. The enemy will only trophy. This property in science is called autotomy. The muscles of the tentacles begin to contract so much that it causes a rupture. Literally in a day, the wound begins to heal, and the limb grows back again. You say, like a lizard. But no. The lizard is able to throw off the tail only in a certain place, no more, no less. And the octopus can tear off its "hand" wherever it wants.
The internal structure of the octopus
The octopus has a huge brain that protects the cartilage capsule (skull). The brain consists of 64 lobes and even has the beginnings of the cortex. Biologists compare the intelligence of an octopus with the intelligence of a domestic cat. The octopuses are capable of emotions and are very smart. They have a good memory and are even able to distinguish between geometric shapes.
Like other creatures, octopuses have a liver, stomach, glands and intestinal tract. Thus, the esophagus on the way to the stomach permeates the liver and brain. The esophagus is very thin, so before swallowing food, a pretty octopus crushes it with a "beak." Then, already in the stomach, it digests food with the help of digestive juice, which is produced by the liver and pancreas. In the stomach of an octopus there is a process - tsekum, which is responsible for the absorption of nutrients. The octopus liver is a large, oval-shaped brown organ. It performs several functions at once: it absorbs amino acids, produces enzymes and stores nutrients.
In the back of the skull are the organs of equilibrium - statocysts. These are bubbles, inside of which there is a liquid and lime stones (statolites). When the body of an octopus changes its position in space, the pebbles move and touch the walls of the bubbles covered with sensitive cells, which strongly irritates the octopus. In this way he can navigate in space even without light.
In a special process of the rectum, the octopus stores a supply of poisonous ink, which serves as an excellent means of protection. The integuments (or rather, the octopus mantle) contain specific cells: chromototophores and iridiocytes, which are responsible for the ability to change color. The first ones contain black, red, brown, yellow and orange pigments. The latter allow the octopus to stain with a purple, green, blue or metallic shade.
Octopus has a highly developed circulatory system. The muscles and skin in many places have capillaries that serve to move the arteries into the veins.
How do they work?
So, the octopus has three hearts. One is the main thing that drives blood all over the octopus body. This heart consists of two atria and a small ventricle. And one more heart near each gill (there are two of them in the octopus). These hearts are smaller. They help the main muscle push blood through the gills, whence it, already filled with oxygen, returns to the atrium of the large heart. Therefore, they are called "gill."
Regardless of how many hearts an octopus has, they all beat the same. The frequency of their contractions depends on the temperature of the water in which the creature is located. So, the colder the water, the slower the hearts beat. For example, at a temperature of 20-22 degrees the muscles contract about 40-50 times per minute.
By the way, the heart of the octopus, or rather the heart, is far from the only feature of the mollusk. Very peculiar and his blood. She imagine, blue! The fact is that it contains the enzyme hemocyanin, which contains copper oxides.
What surprises people octopuses?
Octopuses are unusual, they excite the human imagination, cause fear and even horror. For scientists, these mollusks have always been of particular interest. As we studied, it turned out that they had a peculiar structure: a huge brain, an unusual system of digestion, a characteristic way of movement in the aquatic environment. But the most surprising was the fact that the octopus is not one, but three hearts at once.
This feature is for certain known and well studied. In any octopus - and the smallest, located at the end of the finger, and four-meter giants - the circulatory system is arranged in this way.
How do octopus hearts work?
First of all, let's remember how the circulatory system of any animals functions. The heart pushes blood to the respiratory organs (in humans it’s the lungs, in the octopus it’s the gills), where it is saturated with oxygen. Then this enriched blood enters the heart, which directs it to all organs to ensure their breathing and metabolic processes.
As a rule, a single heart copes with this work, but for octopus, nature has come up with another scheme. He has two functions (oxygen capture and delivery throughout the body) are divided between one main and two additional hearts. The main heart of the mollusk in its structure and physiology resembles the hearts of developed vertebrates. It consists of three chambers and serves to fill all organs with blood. By the way, three cameras are a great evolutionary achievement! Even the fish have only one camera, and only amphibians that came to the land "came up with the three-chamber structure"!
Two extra hearts push blood through the gills with great force, where it receives the necessary oxygen. They are located next to the gills - one for each - and are called "gill".
Thus, the three hearts of the marine mollusk work harmoniously.
Why do octopuses have so many hearts?
If most of the living creatures have one heart, then why did the octopus take as many as three? The fact is that its gills are very dense, taut. To push the blood through them, you need considerable effort.
In the case of the octopus, evolution “made a witty decision”: it divided the work between three hearts. Additional overcome the resistance of the gills, so that the blood and receives oxygen.
Why are octopuses called "sea aristocrat"?
Octopuses deservedly enjoy the reputation of unusual creatures, because even their blood is the very true blue hue! Hemocyanin molecules attach it.
Hemocyanin is an analogue of hemoglobin and serves to transport oxygen, that is, for respiration. But if hemoglobin contains iron salts, then hemocyanin contains copper salts. Therefore, the person and other warm-blooded blood is red, and the "sea aristocrat" - blue.
Who has a few more hearts?
The presence of several hearts is extremely rare in nature. Species of animals with a similar feature can be counted on the fingers. In addition to octopuses, earthworms and mixin are not single hearts - extremely unpleasant creatures living in the seas. The circulatory system of earthworms is primitive: it consists of two vessels extending through a long body. In order to drive blood, there are a number of muscle bulges in the vessels, which can be called hearts.
Mixin has four hearts - the main and three additional. Probably having several hearts is one of the reasons for the amazing vitality of these monsters.
Paleontologists have suggested that the brontosaurs, the enormous fossil lizards who possessed a long neck, also had several hearts. Otherwise, how could blood overcome gravity, rising several meters to the head of a dinosaur?
By the way, a person can also have more than one heart, only this is not the norm, but a game of nature. People with two synchronously working hearts can live happily ever after - in the history of medicine such cases were recorded, although very rarely.